clang-format: add support for clang-format
clang-format: add support for clang-format

Add .clang-format style from linux kernel to allow easier
style formatting for developers that do not use uncrustify.
You can call "clang-format -style=file -i my_src.c" within the repo
to in-place fix the style.

Signed-off-by: Håkon Alseth <ba2ed1ab4e9253b1056dac293cf64821b7379792@nordicsemi.no>

explora26/zephyr,galak/zephyr,punitvara/zephyr,punitvara/zephyr,finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,Vudentz/zephyr,Vudentz/zephyr,finikorg/zephyr,GiulianoFranchetto/zephyr,explora26/zephyr,Vudentz/zephyr,finikorg/zephyr,ldts/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,punitvara/zephyr,finikorg/zephyr,finikorg/zephyr,punitvara/zephyr,GiulianoFranchetto/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,punitvara/zephyr,nashif/zephyr,explora26/zephyr,explora26/zephyr,GiulianoFranchetto/zephyr,explora26/zephyr,ldts/zephyr,ldts/zephyr,Vudentz/zephyr,galak/zephyr,nashif/zephyr,ldts/zephyr,GiulianoFranchetto/zephyr,GiulianoFranchetto/zephyr,nashif/zephyr,ldts/zephyr,zephyrproject-rtos/zephyr